Curcumin Conjugates Induce Apoptosis Via a Mitochondrion Dependent Pathway in MCF-7 and MDA-MB-231 Cell Lines

Abstract

In order to enhance the bioavailability of curcumin its conjugates with piperic acid and glycine weresynthesized by esterifying the 4 and 4’ phenolic hydroxyls, the sites of metabolic conjugation. Antiproliferativeand apoptotic efficacy of synthesized conjugates was investigated in MCF-7 and MDA-MB-231 cell lines. IC50values of di-O-glycinoyl (CDG) and di-O-piperoyl (CDP) esters of curcumin were found to be comparable withthat of curcumin. Both conjugates induced chromatin condensation fragmentation and apoptotic body formation.CDP exposure to MCF-7 cells induced apoptosis initiating loss of mitochondrial membrane potential (Δψm)followed by inhibition of translocation of transcription factor NF-kB and release of Cytochrome-C. Reactiveoxygen species (ROS) production was evaluated by fluorescent activated cell sorter. Change in ratio of Bcl2/Bclxl was observed, suggesting permeablization of mitochondrial membrane leading to the release of AIF, Smacand other apoptogenic molecules. DNA fragmentation as a hallmark for apoptosis was monitored by TUNEL aswell as agrose gel electrophoresis. Thus, it was proven that conjugation does not affect the therapeutic potentialof parent molecule in vitro, while these could work in vivo as prodrugs with enhanced pharmacokinetic profile.P harmacokinetics of these molecules under in vivo conditions is a further scope of this study.